Coastal Ocean Forecast System Research Articles

Advanced Sea Ice Modeling for Short-Term Forecasting for Alaska’s Coasts

Abstract In Alaska’s coastal environment, accurate information of sea ice conditions is desired by operational forecasters, emergency managers, and responders. Complicated interactions among atmosphere, waves, ocean circulation, and sea ice collectively impact the ice conditions, intensity of storm surges, and flooding, making accurate predictions challenging. A collaborative work to build the Alaska Coastal Ocean Forecast System established an integrated storm surge, wave, and sea ice model system for the coasts of Alaska, where the verified model components are linked using the Earth System Modeling Framework and the National Unified Operational Prediction Capability. We present the verification of the sea ice model component based on the Los Alamos Sea Ice Model, version 6. The regional, high-resolution (3 km) configuration of the model was forced by operational atmospheric and ocean model outputs. Extensive numerical experiments were conducted from December 2018 to August 2020 to verify the model’s capability to represent detailed nearshore and offshore sea ice behavior, including landfast ice, ice thickness, and evolution of air–ice drag coefficient. Comparisons of the hindcast simulations with the observations of ice extent presented the model’s comparable performance with the Global Ocean Forecast System 3.1 (GOFS3.1). The model’s skill in reproducing landfast ice area significantly outperformed GOFS3.1. Comparison of the modeled sea ice freeboard with the Ice, Cloud, and Land Elevation Satellite-2 product showed a mean bias of −4.6 cm. Daily 5-day forecast simulations for October 2020–August 2021 presented the model’s promising performance for future implementation in the coupled model system. Significance Statement Accurate sea ice information along Alaska’s coasts is desired by the communities for preparedness of hazardous events, such as storm surges and flooding. However, such information, in particular predicted conditions, remains to be a gap. This study presents the verification of the state-of-art sea ice model for Alaska’s coasts for future use in the more comprehensive coupled model system where ocean circulation, wave, and sea ice models are integrated. The model demonstrates comparable performance with the existing operational ocean–ice coupled model product in reproducing overall sea ice extent and significantly outperformed it in reproducing landfast ice cover. Comparison with the novel satellite product presented the model’s ability to capture sea ice freeboard in the stable ice season.

Impact of larval behaviors on dispersal and connectivity of sea scallop larvae over the northeast U.S. shelf

Sea scallops (Placopecten magellanicus) are a highly fecund species that supports one of the most commercially valuable fisheries in the northeast U.S. continental shelf region. Scallop landings exhibit significant interannual variability, with abundances widely varied due to a combination of anthropogenic and natural factors. By coupling a pelagic-stage Individual-Based scallop population dynamics Model (hereafter referred to as Scallop-IBM) with the Northeast Coastal Ocean Forecast System (NECOFS) and considering the persistent aggregations over Georges Bank (GB)/Great South Channel (GSC) as source beds, we have examined the dispersion and settlement of scallop larvae over 1978–2016. The results demonstrated that the significant interannual variability of larval dispersal was driven by biophysical interactions associated with scallop larval swimming behaviors in their early stages. The duration, frequency, and stimulus of larval vertical migration in the ocean mixed layer (OML) affected the residence time of larvae in the water column over GB. It thus sustained the persistent aggregations of scallops in the GB/GSC and Southern New England region. In addition to larval behavior in the OML, the larval transport to the Middle Atlantic Bight (MAB) was also closely related to the intensity and duration of northeasterly wind in autumn. There was no conspicuous connectivity of scallop larvae between GB/GSC and MAB in the past 39 years except in the autumn of 2009. In 2009, the significant larval transport to the MAB was produced by unusually strong northeasterly winds. Ignoring larval behavior in the OML could overestimate the scallop population’s connectivity between GB and the MAB and thus provide an unrealistic prediction of scallop larval recruitment in the region. Both satellite-derived SST and NECOFS show that the northeast U.S. shelf experienced climate change-induced warming. The extreme warming at the shelfbreak off GB tends to intensify the cross-isobath water temperature gradient and enhance the clockwise subtidal gyre over GB. This change can increase the larval retention rate over GB/GSC, facilitating enhanced productivity on GB.

Variational interpolation of high-frequency radar surface currents using DIVAnd

DIVAnd (Data-Interpolating Variational Analysis, in n-dimensions) is a tool to interpolate observations on a regular grid using the variational inverse method. We have extended DIVAnd to include additional dynamic constraints relevant to surface currents, including imposing a zero normal velocity at the coastline, imposing a low horizontal divergence of the surface currents, temporal coherence and simplified dynamics based on the Coriolis force, and the possibility of including a surface pressure gradient. The impact of these constraints is evaluated by cross-validation using the HF (high-frequency) radar surface current observations in the Ibiza Channel from the Balearic Islands Coastal Ocean Observing and Forecasting System (SOCIB). A small fraction of the radial current observations are set aside to validate the velocity reconstruction. The remaining radial currents from the two radar sites are combined to derive total surface currents using DIVAnd and then compared to the cross-validation dataset and to drifter observations. The benefit of the dynamic constraints is shown relative to a variational interpolation without these dynamical constraints. The best results were obtained using the Coriolis force and the surface pressure gradient as a constraint which are able to improve the reconstruction from the Open-boundary Modal Analysis, a quite commonly used method to interpolate HF radar observations, once multiple time instances are considered together.

Impacts of sea level rise on future storm-induced coastal inundations over massachusetts coast

Hurricanes (tropical cyclones) and nor'easters (extratropical cyclones) are two major storm systems for flood risk over the Massachusetts coast. Severe coastal inundation usually happens when wind-induced waves and storm surges coincide with high tides. A Northeast Coastal Ocean Forecast System (NECOFS) was established and placed into the 24/7 forecast operations starting in 2007. Using a well-validated “end to end” FVCOM inundation model of NECOFS, we examined the impact of climate change-induced sea-level rise (SLR) on the future extratropical storms-induced coastal inundation over the Massachusetts coast. The assessment was done by making the model experiments to project the storm-induced inundation over the coastal areas of Scituate and Boston Harbors with different SLR scenarios under a hundred-year storm condition. The results suggest that with sustained SLR, the northeastern US coast will be vulnerable more severely to wave runup-induced splashing/overtopping than wind-induced storm surges. This finding is consistent with the change in the intensity of storm-generated surface waves in the last decade. The model also suggests that the responses of surge and surface waves to SLR are fully nonlinear. The assessment of the impacts of SLR on the future storm-induced coastal inundation should be investigated with a model including wave-current interactions.

Spatiotemporal variability in the phenology of the initial intra‐annual molt of American lobster (Homarus americanus Milne Edwards, 1837) and its relationship with bottom temperatures in a changing Gulf of Maine

AbstractThis study uses the Maine Department of Marine Resources Lobster Sea Sampling data (2000–2016) and logistic models to develop the first time series for the timing and suddenness of onset of the initial intra‐annual molt of American lobster in the Gulf of Maine (GoM), an annual fishery recruitment event crucial to fishermen. Data from three GoM regions (eastern, central, and western coastal Maine) were further divided by sex and estimated maturity of sampled lobsters for analysis. We found differences in the patterns of initial molt timing and suddenness between the regions, sexes, and stages of maturity. Using the Northeast Coastal Ocean Forecasting System hindcast temperatures, seasonal accumulated degrees above 5°C were used to describe the thermal history for each region at ocean depths of about 5 and 110 m. These temperature metrics were used in generalized linear models to investigate the potential effects of seasonal temperatures on the initial molt season. Results showed that initial intra‐annual molting of lobsters was variable from 2000 to 2016, with periods of both earlier and more sudden molts and later and more protracted molts. Warmer temperatures, specifically inshore temperatures, were generally associated with an earlier molt, but without complete uniformity in the direction and magnitude across seasons, regions, and lobster demographics. We also discuss why developing molt time series and quantifying the connection to the bottom temperatures are necessary and emphasized why existing monitoring programs and the applied quantification techniques herein make this relationship difficult to quantify.

Development and validation of a coastal ocean forecasting system for Puerto Rico and the U.S. virgin islands

An ocean forecasting system has been developed for the coastal area of Puerto Rico and the U.S. Virgin Islands. This paper presents the development and validation of the Puerto Rico Operational Regional Ocean Modeling System (PRO-ROMS) developed by the Caribbean Coastal Ocean Observing System (CARICOOS), which aims at improving currently available short-term forecasts of ocean currents for this region, and to resolve sub-mesoscale variability absent from the currently operational regional systems. The coastal ocean forecasting system is based on the Regional Ocean Modeling System (ROMS), and provides a 3-day forecast of ocean currents, water levels, temperature and salinity. Initial and lateral boundary conditions are derived from the U.S. Naval Oceanographic Office (NAVOCEANO) operational AmSeas forecasting system, a 3.6-km resolution application of the regional Navy Coastal Ocean Model (NCOM) that encompasses the Gulf of Mexico and Caribbean Sea. Meteorological conditions are interpolated from the Navy’s Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) with the exception of surface stresses, which are computed from a 2-km application of the Weather Research and Forecasting (WRF) model used by National Centers for Environmental Protection’s (NCEP) National Digital Forecast Database (NDFD). Tidal variability is imposed using ROMS spectral forcing by specifying the harmonic phases and amplitudes from the TPXO global inverse tide solutions at the boundaries and sub-tidal conditions are imposed by filtering out high frequencies of barotropic variables from the lateral boundary conditions interpolated from AmSeas. Modeled results of sea surface height are validated with NOAA tide gauges, ocean currents are validated with Acoustic Doppler Current Profilers (ADCP) and High Frequency Radars (HFR). Computed statistics show improvement of the ocean current forecast in PRO-ROMS compared to AmSeas, especially at higher frequencies dominated by the tides and in small channels where the bathymetry is better represented by the higher resolution coastal ocean forecasting system.

FVCOM one-way and two-way nesting using ESMF: Development and validation

Built on the Earth System Modeling Framework (ESMF), the one-way and two-way nesting methods were implemented into the unstructured-grid Finite-Volume Community Ocean Model (FVCOM). These methods help utilize the unstructured-grid multi-domain nesting of FVCOM with an aim at resolving the multi-scale physical and ecosystem processes. A detail of procedures on implementing FVCOM into ESMF was described. The experiments were made to validate and evaluate the performance of the nested-grid FVCOM system. The first was made for a wave-current interaction case with a two-domain nesting with an emphasis on qualifying a critical need of nesting to resolve a high-resolution feature near the coast and harbor with little loss in computational efficiency. The second was conducted for the pseudo river plume cases to examine the differences in the model-simulated salinity between one-way and two-way nesting approaches and evaluate the performance of mass conservative two-way nesting method. The third was carried out for the river plume case in the realistic geometric domain in Mass Bay, supporting the importance for having the two-way nesting for coastal-estuarine integrated modeling. The nesting method described in this paper has been used in the Northeast Coastal Ocean Forecast System (NECOFS)-a global-regional-coastal nesting FVCOM system that has been placed into the end-to-end forecast and hindcast operations since 2007.

Surface circulation in Block Island Sound and adjacent coastal and shelf regions: A FVCOM-CODAR comparison

CODAR-derived surface currents in Block Island Sound over the period of June 2000 through September 2008 were compared to currents computed using the Northeast Coastal Ocean Forecast System (NECOFS). The measurement uncertainty of CODAR-derived currents, estimated using statistics of a screened nine-year time series of hourly-averaged flow field, ranged from 3 to 7cm/s in speed and 4° to 14° in direction. The CODAR-derived and model-computed kinetic energy spectrum densities were in good agreement at subtidal frequencies, but the NECOFS-derived currents were larger by about 28% at semi-diurnal and diurnal tidal frequencies. The short-term (hourly to daily) current variability was dominated by the semidiurnal tides (predominantly the M2 tide), which on average accounted for ∼87% of the total kinetic energy. The diurnal tidal and subtidal variability accounted for ∼4% and ∼9% of the total kinetic energy, respectively. The monthly-averaged difference between the CODAR-derived and model-computed velocities over the study area was 6cm/s or less in speed and 28° or less in direction over the study period. An EOF analysis for the low-frequency vertically-averaged model current field showed that the water transport in the Block Island Sound region was dominated by modes 1 and 2, which accounted for 89% and 7% of the total variance, respectively. Mode 1 represented a relatively stationary spatial and temporal flow pattern with a magnitude that varied with season. Mode 2 was characterized mainly by a secondary cross-shelf flow and a relatively strong along-shelf flow. Process-oriented model experiments indicated that the relatively stationary flow pattern found in mode 1 was a result of tidal rectification and its magnitude changed with seasonal stratification. Correlation analysis between the flow and wind stress suggested that the cross-shelf water transport and its temporal variability in mode 2 were highly correlated to the surface wind forcing. The mode 2 derived onshore and offshore water transport, and was consistent with wind-driven Ekman theory. The along-shelf water transport over the outer shelf, where a large portion of the water flowed from upstream Nantucket Shoals, was not highly correlated to the surface wind stress.

Optimal design of a Lagrangian observing system for hydrodynamic surveys

ABSTRACTIn this paper the problem of the optimisation of at-sea campaigns is tackled throughout the implementation of a near real-time decision support system (DSS) for short-term Lagrangian observing platforms. The DSS consisted of two modules: a real-time coastal-ocean forecasting system (CFS), including both hydrodynamic and particle-tracking numerical models, and a module to provide optimised deployment solutions for a set of Lagrangian current-meter buoys. The system was calibrated for a shallow water environment – the Cabras Lagoon in the western Mediterranean Sea. The DSS was then applied to provide in situ optimised measurement strategies during a Lagrangian survey campaign. The different solutions provided by the DSS were verified by real-time measurements and the system was established to be efficient in reducing the cost–benefit ratio and favouring long records and near-synoptic and non-redundant observations.

Evaluation of High-Resolution WRF Model Simulations of Surface Wind over the West Coast of India

This paper presents results from a statistical validation of the hindcasts of surface wind by a high-reso- lution-mesoscale atmospheric numerical model Advanced Research WRF (ARW3.3), which is set up to force the operational coastal ocean forecast system at Indian Na- tional Centre for Ocean Information Services (INCOIS). Evaluation is carried out based on comparisons of day-3 forecasts of surface wind with in situ and remote-sensing data. The results show that the model predicts the surface wind fields fairly accurately over the west coast of India, with high skill in predicting the surface wind during the pre-monsoon season. The model predicts the diurnal variability of the surface wind with reasonable accuracy. The model simulates the land-sea breeze cycle in the coastal region realistically, which is very clearly observed during the northeast monsoon and pre-monsoon season and is less prominent during the southwest monsoon season.  Keywords: WRF, Arabian sea, surface wind field, valida-

Coastal flooding in Scituate (MA): A FVCOM study of the 27 December 2010 nor'easter

[1] A nested Finite-Volume Coastal Ocean Model (FVCOM) inundation forecast model has been developed for Scituate (MA) as part of the Northeast Coastal Ocean Forecast System (NECOFS). Scituate Harbor is a small coastal lagoon oriented north-south with a narrow entrance (with opposing breakwaters) opening eastward onto Massachusetts Bay and the Gulf of Maine. On 27 December 2010, a classic nor'easter produced a ∼0.9 m high surge, which when added to the ∼1.5 m high tide and seasonal higher mean water level, produced significant inundation in Scituate. The Scituate FVCOM inundation model includes flooding/drying, seawall/breakwater, and wave-current interaction capabilities, and was driven by one-way nesting with NECOFS. Hindcasts of the 27 December nor'easter event were made with two different resolution Scituate FVCOM grids with and without inclusion of wave-current interaction to examine the influence of spatial resolution and model dynamics on the predicted flooding. In all simulations, a wind-driven coastal current flowed southward across the harbor entrance, with an attached separation eddy forming downstream of the northern breakwater and rapid decrease in wave energy entering the harbor. With wave-current interaction, the southward coastal current was strongly enhanced and currents within the separation eddy increased to more than 1 m/s, making it highly nonlinear with large lateral shears. Comparisons of the model water elevation time series with harbor tide station measurements showed that inclusion of wave-current interaction increased the peak model surge by ∼8 cm, in closer agreement with the observed peak.

Predictions for oil slicks detected from satellite images using MyOcean forecasting data

Abstract. The pan-European capacity for the Ocean Monitoring and Forecasting (MyOcean) Marine Core Service, implementing the Global Monitoring for Environment and Security (GMES) objectives, targets the provision of ocean state observations from various platforms and analysis and forecasting products to assist, among other downscaling activities, the needs of the operational response to marine safety, particularly concerning oil spills. The MEDSLIK oil spill and trajectory prediction system makes use of the MyOcean regional and Cyprus Coastal Ocean Forecasting and Observing System (CYCOFOS) downscaled forecasting products for operational application in the Mediterranean and pre-operational use in the Black Sea. Advanced Synthetic Aperture Radar (ASAR) satellite remote sensing images from the European Space Agency (ESA) and European Maritime Safety Agency CleanSeaNet (EMSA-CSN) provide the means for routine monitoring of the southern European seas for the detection of illegal oil discharges. MEDSLIK offers various ways, to be described in this paper, of coupling the MyOcean forecasting data with ASAR images to provide both forecasts and hindcasts for such remotely observed oil slicks. The main concern will be the drift of the oil slick and also, in the case of the forecast mode, its diffusive spreading, although some attempt is also made to estimate the changes in the state of the oil. The successful link of the satellite-detected oil slicks with their operational predictions using the MyOcean products contributes to the operational response chain and the strengthening of maritime safety for accidental or illegal spills, in implementation of the Mediterranean Decision Support System for Marine Safety (MEDESS-4MS) regarding oil spills.

Modeling tides and their influence on the circulation in Prince William Sound, Alaska

In the process of developing a real-time data-assimilating coastal ocean forecasting system for Prince William Sound, Alaska, tidal signal was added to a three-domain nested model for the region. The model, which is configured from the Regional Ocean Modeling System (ROMS), has 40 levels in the vertical direction and horizontal resolutions of 10.6km, 3.6km and 1.2km for its three nested domains, respectively. In the present research, the ROMS tidal solution was validated using data from coastal tide gauges, satellite altimeters, high-frequency coastal radars, and Acoustic Doppler Current Profiler (ADCP) current surveys. The error of barotropic tides, as measured by the total root mean square discrepancy of eight major tidal constituents is 5.3cm, or 5.6% of the tidal sea surface height variability in the open ocean. Along the coastal region, the total discrepancy is 9.6cm, or 8.2% of the tidal sea surface height variability. Model tidal currents agree reasonably well with the observations. The influence of tides on the circulation was also investigated using numerical experiments. Besides tides, other types of forcing fields (heat flux, wind stress, evaporation minus precipitation, and freshwater discharge) were also included in the model. Our results indicate that tides play a significant role in shaping the mean circulation of the region. For the summer months, the tidal residual circulation tends to generate a cyclonic gyre in the central Sound. The net transport into the Sound through Hinchinbrook Entrance is reduced. Tides also increase the mixed layer depth in the Sound, especially during the winter months.

The predictability of near-coastal currents using a baroclinic unstructured grid model

A limited domain, coastal ocean forecast system consisting of an unstructured grid model, a meteorological model, a regional ocean model, and a global tidal database is designed to be globally relocatable. For such a system to be viable, the predictability of coastal currents must be well understood with error sources clearly identified. To this end, the coastal forecast system is applied at the mouth of Chesapeake Bay in response to a Navy exercise. Two-day forecasts are produced for a 10-day period from 4 to 14 June 2010 and compared to real-time observations. Interplay between the temporal frequency of the regional model boundary forcing and the application of external tides to the coastal model impacts the tidal characteristics of the coastal current, even contributing a small phase error. Frequencies of at least 3 h are needed to resolve the tidal signal within the regional model; otherwise, externally applied tides from a database are needed to capture the tidal variability. Spatial resolution of the regional model (3 vs 1 km) does not impact skill of the current prediction. Tidal response of the system indicates excellent representation of the dominant M 2 tide for water level and currents. Diurnal tides, especially K 1, are amplified unrealistically with the application of coarse 27-km winds. Higher-resolution winds reduce current forecast error with the exception of wind originating from the SSW, SSE, and E. These winds run shore parallel and are subject to strong interaction with the shoreline that is poorly represented even by the 3-km wind fields. The vertical distribution of currents is also well predicted by the coastal model. Spatial and temporal resolution of the wind forcing including areas close to the shoreline is the most critical component for accurate current forecasts. Additionally, it is demonstrated that wind resolution plays a large role in establishing realistic thermal and density structures in upwelling prone regions.

Modeling tides in Monterey Bay, California

Abstract In the process of developing a tide-permitting coastal ocean forecasting system, tidal signals are added to an oceanic general circulation model for Monterey Bay, California. The model, which is configured from the regional ocean modeling system (ROMS), has three one-way nested domains with the finest resolution of 1.6 km in the horizontal direction and 32 levels in the vertical direction. In present research, the tidal simulation of the system is validated against tide gauges, ADCP current observations, high-frequency radar surface-current observations, and compared with the output from two barotropic tidal models. The results indicate that the barotropic tides from the model compare well with observations in terms of sea-surface height, with discrepancies in amplitude of less than 10% of the amplitude of the most energetic M 2 constituent. However, the discrepancy for the barotropic tidal currents can reach 30% among models with similar accuracy in sea-surface height. The generation and propagation of baroclinic tides associated with the Monterey Submarine Canyon are qualitatively reproduced by the model with weaker strength. The surface tidal current simulation is improved, especially in terms of magnitude, when the model has a more realistic stratification through changes in both barotropic and baroclinic tidal currents.

Operational ocean forecasting in the Eastern Mediterranean: implementation and evaluation

Abstract. The Cyprus Coastal Ocean Forecasting and Observing System (CYCOFOS) has been producing operational flow forecasts of the northeastern Levantine Basin since 2002 and has been substantially improved in 2005. CYCOFOS uses the POM flow model, and recently, within the frame of the MFSTEP project, the flow model was upgraded to use the hourly SKIRON atmospheric forcing, and its resolution was increased from 2.5 km to 1.8 km. The CYCOFOS model is now nested in the ALERMO regional model from the University of Athens, which is nested within the MFS basin model. The Variational Initialization and FOrcing Platform (VIFOP) has been implemented to reduce the numerical transient processes following initialization. Moreover, a five-day forecast is repeated every day, providing more detailed and more accurate information. Forecast results are posted on the web page http://www.oceanography.ucy.ac.cy/cycofos. The new, daily, high-resolution forecasts agree well with the ALERMO regional model. The agreement is better and results more reasonable when VIFOP is used. Active and slave experiments suggest that a four-week active period produces realistic results with more small-scale features. For runs in September 2004, biases with remote sensing sea surface temperature are less than 0.6°C with similar expressions of the flow field present in both. Remotely-observed coastal upwelling south of Cyprus and advection of cool water from the Rhodes Gyre to the southern shores of Cyprus are also modeled. In situ observed hydrographic data from south of Cyprus are similar to the corresponding forecast fields. Both indicate the relatively fresh subsurface Atlantic Water and a near-surface anticyclone south of Cyprus for August/September of 2004 and September 2005. Plans for further model improvement include assimilation of observed XBT temperature profiles, CTD profiles from drifters and gliders, and CT data from the CYCOFOS ocean observatory.

Development of an Ocean Forecasting System off the West Coast of the United States: Sea Level Applications

In the context of continuing development and implementation of global and regional ocean observing systems, we describe here the need and essential ingredients for a coastal ocean forecasting system focused on sea level and associated inundation issues and applications. Such a system must consist of the following key components: 1) satellite and in situ observations, 2) atmospheric forcing, 3) ocean circulation and tide modeling, 4) data assimilation for initialization, 5) forecast error estimation, and 6) data and model management. We describe these components, their continuing development and integrated implementation and application as part of a prototype coastal ocean forecast system for the U.S. West Coast. The multiscale nested modeling approach utilized here has demonstrated that sea level simulation can be improved by increasing the spatial resolution of observations. This and other regional ocean forecast systems are complementary and necessary elements of the emerging Global Ocean Observing System (GOOS) needed to predict changes in sea level. Building on the increasing maturity of ocean observing and forecasting capabilities, there are a number of significant challenges that require immediate attention, planning and development. These include: 1) further development of models, data assimilation algorithms and information management system, 2) adaptive sampling to reduce uncertainty in ocean forecasting, 3) Observing System Simulation Experiments (OSSE) to optimize observing system design, 4) bridging the land-sea boundary, and 5) moving from measurements to information in support of management and decision-making.

A regional ocean modeling system for the Long‐term Ecosystem Observatory

A coastal ocean forecasting system was developed for the Long‐term Ecosystem Observatory (LEO) on New Jersey's inner shelf. The forecast system comprised an ocean model, the Regional Ocean Modeling System, forced by a high‐resolution atmospheric forecast, with assimilation of ocean data from ships and coastal radar systems. The forecasts were used to aid the deployment of real‐time adaptive sampling observing systems during the July 2001 Coastal Predictive Skill Experiment. Temperature and salinity assimilation data were prepared by optimal interpolation of shipboard towed‐body data. Surface current observations from coastal radar were projected vertically for assimilation using a statistically based extrapolation. The assimilation methods tested with the operational forecast system in July 2001 were continuous nudging and intermittent melding of the model forecast and gridded data. Observations from a validation array of current meter and thermistor moorings deployed on a cross‐shore line through the center of the LEO intensive observing area were used to formulate a set of quantitative model skill metrics that focused on aspects of the two‐layer wind‐driven upwelling and downwelling circulation that characterizes ocean dynamics during the stratified summer season along this coast. An ensemble of model and data assimilation configurations were tested, showing that the k profile parameterization for vertical turbulence closure, and assimilation by intermittent melding, comprised the forecast system with the more significant skill as measured by the mean squared error of the validation metric time series.

An Operational European Global Ocean Observing System for the Eastern Mediterranean Levantine Basin: The Cyprus Coastal Ocean Forecasting and Observing System

The countries surrounding the Mediterranean Sea have joined together in several multinational initiatives to conduct long-term, integrated, operational oceanographic observations and modelling of this important region. Some of these initiatives and the country members involved are discussed in this paper. Particular emphasis is given to long-term observing systems and modelling conducted in the Eastern Mediterranean Levantine Basin and the region around the island of Cyprus. A complete operational oceanographic forecasting and observing system has been developed in Cyprus, and has been operational since early 2002. The system is called CYCOFOS—Cyprus Coastal Ocean Forecasting and Observing System—and is a component of the Global Ocean Observing System (GOOS), and its European (EuroGOOS) and Mediterranean (MedGOOS) modules. CYCOFOS is the result of several years of research activities all carried out within the framework of European Union-funded projects including: (1) Mediterranean forecasting system, both pilot project and towards environmental predictions (MFSPP and MFSTEP), (2) Mediterranean network to Access and upgrade Monitoring and forecasts Activities in the region (MAMA), (3) European Sea level Service Research Infrastructure (ESEAS-RI), (4) Mediterranean network of Global sea Level Observing System (MedGLOSS), and (5) Marine Environment and Security in the European Areas (MERSEA strand 1). CYCOFOS at present consists of several operational modules, including flow and offshore waves forecasts, satellite remote sensing, coastal monitoring stations and end user-derived applications. All these operational modules provide regular near-real-time information, both to local and sub-regional end users in the Eastern Mediterranean Levantine Basin. This paper discusses these as well as additional ocean observation stations and features soon to be added to CYCOFOS.

Assimilation of SST Data into a Real-Time Coastal Ocean Forecast System for the U.S. East Coast*

Abstract The real-time, three-dimensional, limited-area Coastal Ocean Forecast System (COFS) has been developed for the northwestern Atlantic Ocean and implemented at the National Centers for Environmental Prediction. COFS generates a daily nowcast and 1-day forecast of water level, temperature, salinity, and currents. Surface forcing is provided by 3-h forecasts from the National Weather Service's Eta Model, a mesoscale atmospheric prediction model. Lateral oceanic boundary conditions are based on climatic data. COFS assimilates in situ sea surface temperature (SST) observations and multichannel satellite SST retrievals for the past 48 h. SST predictions from the assimilating and nonassimilating versions of COFS were compared with independent observations and a 14-km-resolution multichannel SST analysis. The assimilation of SST data reduced the magnitude and the geographic extent of COFS's characteristic positive temperature bias north of the Gulf Stream. The root-mean-square SST differences between the ...